The present invention relates to a method and apparatus for winding a continuously advancing yarn into a yarn package.
When winding a continuously advancing yarn into a package against whose circumference a contact roll bears with a contact force, the build of the package is accommodated by a yielding movement of the package or a yielding movement of the contact roll. DE 40 18 095 and corresponding U.S. Pat. No. 5,100,072 disclose a winding mechanism for winding freshly spun yarn in which the yielding movement of the package support is regulated during the winding run in accordance with the position of the contact roll. In this case, the package support comprises a spindle which is rotatably mounted on a rotatable revolver, and the yielding movement of the support spindle is achieved by rotating the revolver. The contact roll is mounted on a pivotable support, so that it can execute a movement in the radial direction with respect to the package during the winding run. The movement of the contact roll support is sensed and fed to a control device, which causes the revolver to rotate with the support spindle in accordance with the travel of the contact roll.
The package support spindle of winding machines of this kind is subject to vibrations during winding, in particular in the lower rotational speed range of &lt;2,000 rpm, which severely disturb the package winding operation. Moreover, the radial movement of the contact roll results in a further increase in vibrations of this kind.
DE 32 07 375 discloses a winding mechanism for winding yarn in which the package support is pivotably mounted by means of a pivot shaft. The known winding mechanism is primarily employed in texturing machines at yarn speeds of up to 1,200 m/min. A package holder is disposed at the free end of the support to take up the package. The package bears against a stationary, driven contact roll. During the winding process, the increasing package diameter causes the package support to move radially with respect to the contact roll. Because the package support can move freely, this arrangement may also suffer vibrations which are unchecked and have a significant detrimental effect on the winding process. Although it is known to damp the movement of the package support in the direction of movement in winding mechanisms of this kind, this case entails the problem of high hysteresis forces, which result in significant variations in the contact force between the contact roll and the package surface, when a vibration-induced reversal of movement occurs.
It is accordingly an object of the invention to provide a method and apparatus for winding a continuously advancing yarn in which a substantially hysteresis-free damping of the yielding movement of the freely movable support (package support or contact roll support) takes place when winding a package, so that winding can also be carried out at extremely low winding speeds.